Power sweeper broom



y 22, 1951 A. E. CARLSON ET AL 2,553,748

POWER SWEEPER BROOM Filed Dec. 22, 1945 y 2, 1951 A. E. CARLSON ET AL 7 53,748

POWER SWEEPER BROOM Filed Dec. 22, 1945 3 Sheets-Sheet 2 7%; C4 M/V May 22, 1951 A. E. CARLSON ET AL 2,553,748

POWER SWEEPER BROOM Filed Dec. 22, 1945 3 Sheets-Sheet 3 [IT-VET? 2 SP5 fer/1m a Qmsa/y- Patented May 22, 1951 POWER SWEEPER BROOM Arthur E. Carlson, Elgin, and Carl W. Mott, La

Grange Park, Ill.,

assi Company, Elgin, 111.,

gnors to Elgin Sweeper a corporationof Illinois Application December 22, 1945, Serial No. 636,819 9 Claims. (01. 15-482) This invention relates to improvements in rotary brooms and more particularly concerns improvements in the structure and method of making rotary cylindrical brooms of the type which are especially adapted for use in power sweepers such as are employed in street cleanmg.

An important object of the present invention is to provide a rotary broom of the character stated having a new and improved structure for mounting the bristles.

Another object is to provide a novel sweeper broom in which the bristles are conveniently replaceable upon becoming worn out, and in which the core or drum, upon which the bristles are mounted, is of an especially durable and deterioration and wear resisting nature to assure long life for repeated reuse.

Still another object of the invention is to provide a rotary sweeper broom in which the bristles are mounted in a new and improved manner whereby to afford unusually efficient sweeping action, taking full advantage of the inherent resiliency of the bristles, while at the same time minimizing wear of the bristles from friction or bending stresses.

Yet another object of the invention is to provide a new and improved rotary power sweeper broom in which although the bristles form an efficiently uniform and pliable sweeping periphery, the inner or base portions of the bristles are disposed in relatively open rows and in such a manner as to avoid the accumulation of sweepings therebetween, thus saving the bristles from the clogging and deteriorating effects of such accumulations.

A further object of the invention is to provide a power sweeper broom having a substantially self-cleaning and ventilating rotor or drum construction.

A still further object of the invention is to provide a power sweeper broom having an open framework structure carrying the bristles and through and from which dirt and debris working in through the bristles can pass relatively freely.

It is also an object of the invention to provide a new and improved method of making a power sweeper broom.

Certain general featuresof the invention reside in a rotary sweeper broom in which the bristle mount or drum structure is supported by spiders mounted upon or adapted to be mounted upon a driven shaft, the bristle drum structure comprising a relatively open framework on which the bristles are supported in a helical groove structure with ample through spaces between the coils of the helix at the base portions of the bristles to avoid the catching or accumulation of sweeping debris, the groove structure being constructed to afford improved working flexure of the bristles with minimum and well distributed bending stresses.

Another feature of the invention resides in the spiral groove construction of the drum or bristle mount portion of the broom according to which the groove is provided by a channel structure supported by longitudinally extending radially inwardly projecting reinforcing and attachment ribs or bars by which the drum is secured to spiders for mounting upon a drive shaft, the bristles being replaceably secured within the channel groove by a flexible binding element such as a cable which is drawn taut and is releasably secured at the ends of the channel.

It is also a feature of the invention to provide a new and improved method of making a power sweeper broom according to which the bristle-carrying channel is formed from sheet metal into helical drum shape and reinforced by permanently securing rein-forcing bars to extend longitudinally internally of the helical structure to complete the drum.

Other objects, features and advantages of the invention will be readily apparent from the following detailed description taken connection with the accompanying three sheets of drawings in which:

Figure 1 is a small scale elevational view of a rotary power sweeper broom embodying the Teatures of the invention;

Figure 2 is an enlarged end elevational view of the sweeper broom;

Figure 3 is a fragmentary elevational view of a modified broom structure;

Figure 4 is a fragmental elevational view of the sweeper broom structure with certain parts broken away or in section to reveal details of construction;

Figure 5 is a schematic view showing certain steps in the method .of making the bristle-supporting helical channel .of the broom.

Figure 6 is a fragmentary side elevational View of the sweeper broom showing a modified supporting spider and cable terminal securing er clamping structure;

Figure 7 is an end elevational view hi the construction shown in Figure 6 and Figure 8 is :an exploded assembly view of the cable terminal clamping structure utilized in the form of the invention shown in Figure 6.

A sweeper broom 10 (Figures 1 and 2) embodying the features of the present invention is adapted to be of a size large enough to serve as the main power driven rotary cylindrical broom of a street sweeping machine. To this end, the broom It] comprises a generally cylindrical mass of bristles I I supported on a rotor or drum structure l2 which in turn is adapted to be mounted upon a driven shaft l3. The length and diameter of the broom l will be proportioned to the particular requirements of the sweeper with which used. The bristles H, sometimes also referred to as fibers, will be of any kind preferred or best suited for the particular working conditions to which they are to be subjected.

According to the present invention, the bristles H are mounted in an improved readily replaceable manner upon the drum 12 which is of a novel construction. Hence, the drum l2 comprises means such as a radially outwardly opening helical channel l4 providing a continuous groove l5 within which the bristles H are replaceably secured by means such as a tensioned flexible element ll which may comprise a length of steel cable or rope wound into the groove. For this purpose, the bristles H are of initial length approximately twice that required for their working length and are doubled upon themselves to provide what is in effect a base loop [8 seating within the groove l5 and receiving the flexible tying element l'l therethrough whereby the bristles are held securely assembled with the channel [4.

In a preferred form, as best seen in Figure 4, the channel I4 is of substantially U-shape cross section, with a relatively flat base or web and substantial parallel radially extending side walls which are flared outwardly as indicated at [9. The diameter of the flexible securing element 11 is so proportioned to the width of the channel groove [5 and the thickness of the bristles in the loop l8 that a very tight clamping action of the flexible element and the walls of the groove is effected upon the bristle loop when the flexible element is drawn under tension into the groove. Thus, the bristles are anchored quite securely since the bristle loop 18 is driven by the flexible element not only against the base of the channel but also against the side flanges thereof. Since the side flanges of the channel M are formed with the outward flaring lip 19, flexing of the bristles ll laterally of the channel without undue stress or wear is facilitated, and the bending stresses I upon the base portion of the bristles are widely distributed, with the side wall flanges of the channel and the flares l9 backing up the bristle base portions to accomplish this.

In order to afford a relatively uniform, co-

operative relationship of the brushing tips of the bristles II at the periphery of the broom and yet maintain adequate spacing between the helical coils of bristles to avoid crowding and frictional interference with proper and efficient flexing and whipping of the bristles during a sweeping operation, the pitch of the channel I4 is properly predetermined for any particular size of broom or type of bristle to be used to afford substantial space between the adjacent coils of the channel.

An advantageous method of making the bristle mounting channel member [4 is by forming the same from a strip of sheet metal 20 (Figure 5). By the action of suitable forming mechanisms, such as forming rolls (not shown) of a type well 4. known in the sheet metal forming art, the strip is continuously and progressively shaped to the desired channel section, and the helical formation imparted thereto. It will be evident that by relatively simple adjustments in th forming tools, the length or diameter or channel size of any helical section to be incorporated in a broom can be predetermined for any particular broom size, and a large quantity of helical members can be produced quickly and economically. By preference, individual helical channel sections of only a relatively small number of coils are formed and as many sections then joined together end to end as necessary to afiord the desired over-all length for the channel M. In practice, uniform five-coil helical sections have been found to give excellent results. The ends of joined sections may be welded together as indicated at 20:; (Figure 4). The sheet metal strip 28 may be of a non-rusting, non-corroding alloy, such as stainless steel or other relatively deterioration resistant composition or alloy, or the channel l4 may be plated or otherwise treated or rustproofed and protected against deterioration.

When the helical channel 14 is made from sheet metal as suggested, the coils thereof will be relatively resilient. them to yield and deflect undesirably in response to certain pressures either in an axial or radial direction. However, by providing longitudinal reinforcing means such as bars 2| interiorly of the helix, any tendency toward such deflection is prevented. By preference, a plurality of the reinforcing bars 2| is provided and spaced equidistantly about the inner circumference of the helix and of uniform length to extend from end to end and preferably slightly beyond the opposite ends of the helix. As shown in Figures 2 and 4, four simple flat rectangular bars 2| are provided which are secured at one respective longitudinal edge on quadrantly spaced longitudinal lines to the inner circumference of the helix, as by welding them to the flat bases of the channel [4. In this way the coils of the helix are secured in uniformly spaced relation and are held to a substantially perfect cylinder. Since the greatest structural strength of the bars 2| is in their plane which is at right angles to the sides of the channel M, a mutually reinforcing relationship is established which provides a very sturdy framework that is highly resistant to deflection or distortion in any direction. It will be noted that since the reinforcing bars 2| are relatively thin, and the coils of the bristle mounting channel 14 are relatively widely spaced, the framework of the drum l2 provides a substantially uniform open-work pattern through which sweeping debris that work inwardly among the bristles can pass rather freely and thus avoid clogging the broom and interfering with free sweeping flexing action of the bristles l I. Moreover, the open framework of the bristle mounting drum, affords free ventilation about the bristle bases and this/taken with the freedom from accumulation of sweepings thereat, assures substantial freedom from moisture which would tend to cause rotting or deterioration of the bristles.

The reinforcing bars 2| are utilized as a medium for securing the bristle drum 12 concentrically about the shaft l3. To this end, the bars 21 extend to a substantial extent radially inwardly and are engaged by spiders 22 having arms 23 which are secured to the bars by means such as pairs of bolts 24. By preference the barengaging faces of the spider arms 23 are formed This may tend to cause with rabbets providing shoulders 25 for receiving the inner edges of the bars whereby to relieve the bolts 24 of shearing stresses incidentto radial inward pressure against the broom. One of the spiders 22 is secured to each end of the drum structure and as many more of these spiders are secured at intermediate points between the ends as are required for the particular length of the drum. In any event, at least one more spider will be used at, say, the mid-point of the drum which comprises that portion of the drum which is broken away in Figure 4.

Each of the spiders 22 may be of a uniform standard construction and may comprise a suitabl'e casting or forging. For securing the spiders 22 to the broom shaft l3, each may be provided with a central, axially bored hub 26 which may be formed with a keying groove 21 so as to be keyed in well-known manner for rotation with the shaft l3. To lock the spider against longitudinal displacement along the shaft I3, a set screw 28 may be threaded radially through the hub 26 into a suitable locking depression 29 spotted in the shaft. Thus, it will be observed that the bristle-supporting drum i2 and the spiders 22, as a unit, can be mounted or removed from the shaft [3, or the drum |2 can be detached from the spiders 22 by removing the bolts 24 by which the reinforcing and attachment bars 2| are secured to the spiders.

Anchorage of the ends of the flexible peripheral clamping element i! may be effected by means such as J bolts 36. spective opposite ends of the peripheral mounting channel I4 are predetermined to terminate substantially flush with the respective far side of the reinforcing and attaching bar 2| to which such ends are attached. In the present instance, the same bar 2| supports both opposite ends of the channel member which terminate at respectively opposite sides of the bar. Furthermore, the channel ends are secured in radial alignment with the adjacent end spider arms 23. Thereby, the J bolts 36 can be substituted for the regular securing bolts 24 at such arms and with the hooked heads thereof engaging the respective terminal portions of the bristle anchoring element H which extend radially inwardly from the ends of the bristle mounting channel to lie against the face of the bar 2| against which they are securely clamped by the J bolt heads. It will also be noted that in addition to the securement effected by the direct clamping action of the J bolts 30 upon the terminal portions of the flexible element, the sharply inward turn pres ent in the element where the terminal portions leave the channel and lie against the bar 2| effects a snagging action, thus taking advantage of the shear strength of the terminal portions as well as the direct J bolt clamping action to maintain the flexible element under bristle clamping tension.

From the foregoing it will be apparent that the mounting or replacement of the bristles is adapted to be effected expeditiously and economically. In mounting the bristles, a convenient method comprises clamping one terminal portion of the flexible bristle anchoring element i! in place by means of the J bolts 36 and then progressively assembling the bristles 5| either individually or by tufts in the particular concentration desired with the flexible element I7 and into the channel groove I5 and progressively clamping the assembled bristles in place by ind- For this purpose, the re'-' ing the flexible clamping or anchoring element |1 into the channel as rapidly as the bristles are.

assembled therewith and while maintaining the element under tension. This can be effected in any suitable tool or fixture wherein the druln I2 is, for example, gradually rotated to draw the tensioned flexible element into the wound position as the assembly of the bristles therewith progresses. When the opposite end of the mounting channel is reached, the terminal portion of the flexible element at that end is clamped in place by the associated J bolts 36 while the clamping tension on the flexible element is maintained. After the bristles become worn out from use, they can be easily removed by reversing the assembly process just explained except that the flexible clamping element 4'! need not, during the disassembly operation, be held under any more tension than is desirable as a safety factor to prevent whipping. The broom can then be reequipped with bristles as in the first instance, by reusing the bristle anchoring element II or replacing the same with a new element if desirable.

In order to hold the bristles which are exposed at the ends of the broom against undue spreading, dished retainers 3| are preferably secured as by means of screws 32 against the end spiders 22 and concentric with hubs 26 thereof. The margins of the retainers are directed generally axially inwardly toward the bristles, and smoothly turned lips 33 may be formed on the edges thereof for direct non-scuffing, smooth engagement with the bristles.

Where it is desired to afford a more solidly reinforced helical channel drum than with the simple edgewise relationship of the reinforcing and attachment bars 2|, substantially L-shaped reinforcing and attachment bars 34 may be used, as shown in the modified form of Figure 3. To this end, the bars 34 are provided with coil-engaging flanges 35 of substantial width and running the full length of the bars or notched out corresponding to the spaces between the coils of the bristle supporting channel, and conforming in transverse curvature to the curvature of the internal circumference of the helix. Attachment of the flanges 35 may be effected in any preferred manner as by welding, bolting on or the like.

In the form of the invention shown in Figures 6., '7 and 8, the general features of the broom are substantially the same as in the forms of the invention already described but a somewhat different standardized spider 36 is employed which may be in the form of an integral casting provided with generally radially extending spider arms 3! seciu'ed together in pairs at opposite sides of a hub 38 by respective integral sector bars 39, These sector bars 39 are formed on concentric radii and with their circumferences coincident with the circumference of a circle described by the outer end of the spider arms 31. In this manner the respective pairs of arms 37 and their connecting sector bars 39 provide what is in effect a sector frame, and the sector frames are disposed in balanced relationship on diametrically opposite sides of the hub 38.

Each of the spider arms 31 is provided at the respective outer side of the sector frame of which it is a part with a flat seat 40 for receiving a reinforcing and attaching bar 2|. Each seat Qt is disposed in offset parallel relation to a radial plane through the axis of the spider and spaced outwardly from the seat to a distance half the thickness of the bar 2|, thus disposing the bars the respective I radially, Each respective reinforcing and supporting bar 2| may be welded to its spider seat 40.

Radially inwardly of the bar seat 40, each spider arm 37 may be provided with a tapped boss 4| for receiving one of the attaching screws 32 of the bristle guard 3i at the end of the broom at which the spider may be disposed. Of course, where the spider 36 is to be used at an intermediate position of the length of the broom, the bosses 4| need not be tapped.

Although the sector bars 39 have a certain reinforcing value, their principal utility resides in providing respective bases available for securing the terminal ends of the bristle attaching flexible element or cable ii. For this purpose, each of the sector bars 39 is provided with a central inwardly protruding reinforcing boss 42 and is adapted to be formed with a central, radially extending bore 43 for slidably receiving the shank of a stud 44 which forms part of a cable clamp 45. With this arrangement, the cable clamp 45 is disposed approximately 45 from the adjacent end of the bristle mounting channel I4 and the terminal portion of the cable I1 is adapted to be drawn taut against the outer periphery of the contiguous sector bar 39 and to lie alongside the shank of the stud 44. When the stud 44 is then drawn radially inwardly by means of a nut 48 threaded upon its inner end which protrudes beyond the reinforcing boss 42, a clamping plate 41 rigidly carried by the stud is drawn clampingly against the cable terminal. Additional securement of the cable terminal may be effected by affording a suflicient length of cable to extend beyond the initial securement afforded by the clamping plate 41 to wind entirely around the mounting drum over the periphery of the opposite sector bar 39 and return into overlying relation to the clamping plate 41 so that a clamping washer 48 can be driven clampingly thereagainst by a nut 49 threaded onto the outer end portion of the stud 44.

By having the clamping structure 45 formed as a detachable assembly, all of the spiders 36 required for the particular length of the bristle supporting drum may be made according to a standard pattern, and the cable terminal clamping structure 45 is then adapted to be assembled with merely the endmost spiders 36 and then selectively with either of the sector bars 39 of such endmost spiders, as demanded by the location of either of the sector bars adjacent to the respective ends of the bristle mounting channel l4.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention, and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

We claim as our invention:

1. In combination in a rotary sweeper broom, a bristle supporting drum structure including a helical outwardly opening groove wthin which radially outwardly projecting bristles are adapted to be secured by means of a flexible member such as a cable, said supporting structure including end spiders of open construction each of which has a sector bar disposed to extend arcuately beyond the respective opposite ends of the groove to receive the respective terminal end portions of said cable, and clamping structure carried by said sector bars for anchoring the terminal end portions of the cable.

2. In combination in a bristle anchoring drum for a rotary sweeper broom, an end spider structure, said spider having a sector bar, and a clamping structure carried by the sector bar including a stud extending slidably therethrough with a nut secured to its inner end and having a clamping member rigid on its outer portion for engagand clamping the terminal end portion of a bristle anchoring cable against the sector bar when the stud is drawn radially inwardly by tightening said nut.

3. In combination in a rotary sweeper broom, a helical outwardly opening channel providing a groove for receiving radially outwardly extending bristles and adapted to have a flexible bristle securing member tensioned therein, longitudinally extending bars internally reinforcing the helix, each respective end of said channel terminating at a reinforcing bar, and means cooperative with the bar at each such end for anchoring the terminal ends of said bristle securing means.

4. In combination in a cylindrical rotary sweeper broom, a helical sheet metal channel providing a bristle mounting groove, and longitudinal reinforcing bars secured to the base of the channel internally of the helix, each of said bars comprising a flange transversely curved complementary to the curvature of the internalhelix periphery and secured rigidly to the coils of the helix.

5. In combination in a cylindrical sweeper broom, a channel helix formed of sheet metal and providing a channel of substantially flat-base U-shaped cross section affording an outwardly opening groove to receive the bristles for the broom, the coils of the helix being in predetermined spaced relation, and longitudinally extending narrow reinforcing bars secured to the flat base of the channel at the coils thereof and connecting the coils into a substantially rigid open framework, said bars being substantially spaced apart circumferentially about the inner periphery of the helix so as to leave the spaces between the coils of the helix substantially open toward the interior of the helix.

6. In combination in a cylindrical rotary sweeper broom, a helical sheet metal channel member providing an outwardly opening groove for bristles to project radially outwardly from the channel, reinforcing members extending longitudinally internally of the helix and securing the coils of the helix into a substantially rigid framework, a flexible clamping strand wound into said groove for securing the bristles therein and having its terminal portions extending at right angles inwardly from the respective ends of the channel,

and means on one of said reinforcing members for securing said terminal portions thereto and snagging the flexible element at the respective ends of the channel.

'7. A rotary sweeping broom comprising, in combination, a helical bristle channel structure, reinforcing bars extending longitudinally internally of the helix and a spider structure at either end of said channel structure, said spider having a sector bar, and a clamping structure carried by the sector bar including a stud extending slidably therethrough with a nut secured to its inner end and having a clamping member rigid on its outer portion for engaging and clamping the terminal end portion of a bristle anchoring cable against the sector bar when the stud is drawn radially inwardly by tightening said nut.

8. In combination in a cylindrical rotary sweeper broom, a helical sheet metal channel providing a bristle mounting groove, and longitudinal reinforcing bars secured to the base of the channel internally of the helix, each of said bars having transversely curved flanges complementary to the curvature of the internal helical periphery, spaced to conform to the spacing of the helical windings and secured rigidly thereto.

9. In combination in a cylindrical rotary sweeper broom, a helical channel member providing an outwardly opening groove for bristles to project radially outwardly from the channel member, a flexible clamping strand Wound into said groove for securing the bristles therein and having its terminal portions extending at right angles in- Wardly from the respective ends of the channel member, and means for securing said terminal portions in said right angular relation and snagging the flexible element at the respective end of the channel member.

ARTHUR E. CARLSON. CARL W. MOTT.

10 REFERENCES CITED The following references are of record in the file of thisv patent:

UNITED STATES PATENTS Number Name Date 656,761 Adams Aug. 28, 1900 1,126,531 Liebman 1 Jan. 26, 1915 1,168,849 Butler Jan. 18, 1916 1,199,780 Goodrich Oct. 3, 1916 1,963,045 Bickel June 12, 1934 2,045,373 Scully et a1. June 23, 1936 2,332,490 Rowland Oct. 19, 1943 2,349,643 Wesemeyer May 23, 1944 

